Art of spring manufacture.



S. W. BALDWIN.

ART OI' SPRING MANUFAGTURE'. APPLICATION FILED Nov. 5,1904.

^ 908,440. A Patennd L1311.5,1909

l, the bar or coil maintains heat imparted to the metal thereof while in the ingot or billet,

STEPHEN W. BALDWIN, OF NEW YORK, N. Y.

Parana orme.

ART os SPRING MANUFACTURE.

Specication of Letters Patent.

Patented Jan. 5, 1909.

Application filed November 5, 1904. Serial No. 231,466.

To all whom it may concern.'

Be it known that l, STEPHEN W. BALDWIN, a citizen of the United States, residing in Manhattan borough, city of New York, in I the county `of New Yori-Y and Stateof New l York, have invented certain new and useful Improvements in the Art of Spring Manu- E facture, of which the following is a spcciii cation. j l

This invention relates to the art of manu facturing springs, and has for its object to provide a method of vmaking tempered I coiled springs and particularly compression spings of short length from long bars or ro s.

Compression springs, particularlyA those employed in railroad cars and locomotives, are made up in short coils having the ends beve'ed so as to give a squareengaging surface at each end ofthe coil.

The present invention contemplates the production of tempere coiled springs from' an ingot or billet by one heat. The billet or ingot being heated to asufiicient degree of temperature to enableit to be passed through arod or bar rolling mill, passing the same through such mill until a finished bar is delivered therefrom and immediately upon the delivery ofthe bar, ceiling the same into a coil o diameter and pitch corresponding to the completed spring-,coih and then while hardening or tempering the coil, and then cutting the coil up into short lengths, and in such cutting beveling or chamfering the ends of the coils to give each a square end to enga e the abutments in connection with Whic it will perform its work.

In rolling round bars it is frequentlyf the custom to give the bar alternately an elliptical and a round cross-sectional formation,l the last pass, of course, in finishing the bar, giving it its comvleted round shape. The action of the rols upon the bar forges it down giving it a compact andiiinished surface, which compacting and closeness of grain willextend inwardly for a considerable distance, and in some instances may extend throughout the entire bar. 'lf the rolling is done with sulliciont rapidity thel bar will issue from the =iinishing pass with heat enough 'to permit it tol be coiled, and it the coiling is also done with sullicicnt alacrity the coil Willmaintain enough of the heat given to its inetal when in the ingot to permit it to be passed into a bath and hardened.-

I f the bar is permitted to cool and is then reheated, as for instance for the purpose of tempering or for coiling, the outside of the bar or its outer shell or tube will become of a coarser texture than the bar was when it left the rolls, the expansion ofthe particles of steel tending to press and yield away from each other leaving minute interspaces which can only be reduced by a for ing action, but when the'spri'ng fresh from t e action of the rolls is thrown into the tempering bath it will in addition to the temper also carry with it the compactness and closeness of grain produced by the rolling o eration. And in cooling and reheating t 1ere is a, certain amount of scale formation produced which will not be present in ca'ses in which the vspring is thrown directly or immediately into the bath upon its emergence from the roll, plnd tempered at the iinished rolling mill eat.

The coil may be dropped into a bath and hardened and then tempered, but in man instances the heat remaining in the coil will upon its plunging into the bath be just Sunicient to give the proper spring hardness and elasticity Without having resort to drawing or tempering the hardness.

Springs which are 'produced by forcing a hot bar into a ceiling device as contredistinguished from wrapping the bar about a mandrel by the rotation of the mandrel to produce the coil, have certain characteristics which are lacking in such latter form of spring manufacture. And owing to the fact that in finishing the bar from itsv ellip tical to itsv round formation the finishing rolls firmly grip or bite the rod and advance it with acertain amount oi irresistible force, vSuch force may be utilized for pushing the bar through a ceiling device and the coiling device may be placed contiguous to the rolls to gain the llull benefit of the force ol' `advance of thebar, and also to have the barcoilod before the heat has had an opportunity to diminish through contact with the v atmosphere.

hitter the bar has come from the rolls and after it has passed through the ceiling device. the core is hotter than the Walls. The outer surface is smooth and perfect because of the forging action of-the Walls.-

The mass tlu'ougl'i its whole section c0mpasted .fmfl in this condition it is: inuuefli- Maly plunged into the lmn'lening; bath. In

and if plunged inw Llu tei'upuring balli in' this con@ 1011 the msuls me not su goo-il under the former smuliions whpn the bm or coil is plunged into the. lmtli immediately as it cones; from the allg :mul not 'wheat-sul.

The culling is dun@ it tlm rolling; mill spew and the to spi-ing tiiipef doitai. swpioxim'atly. tlm 'lizfiislied vulling mill heat.

Although tlm memoll 0i" my press-,ut inm mation may be carried out in immy differ-- am Wezys, yefu' lor the purpose of more clearly illustrating the nature of the invention, the drawings accompanying and forning :i part of this specification illustra@- iieclmnism' which muy be employed. in practicing 'he, present invention.

v Figuie l shows perspec'fiv@ View of thc ends of n pair ol' yelling mill Tolls, a coiliiig device und in hardening lm i tank shown in csoss-scction, Whisk device may used in alle cmiying out of my improved 'ntliol Fir. is aplam View ol one of lili@ willI mul a iorizontal sentan of the calling d mii shown in l. Fig. 3 is fi @11mm-Suction fzfmough the wuiking periph nl' tlm rolls and through the bm', auch vieu being liu'gm liC blism thai, Shown in l. lio. el a. coss-section 0i' the bm' before 1i; has entered the "finishing pass illusnzmfd in 3. 5 is :i plu-n View. Ol e device lui cuti. sawing the coil into spring lengths, :mil is a side View Oi" a. Spring which ius-y in@ 'tlm pmduot 0l' h@ pesent method. his allow ay com iessifm sp mg but .it will be appui that bilis method. is equally adapted to lie piwluction of exnsifm springs. Many Gl the paz-ts in this ilrmviig :we out of pioportion to other parts und certain pui-ts are shown mom iliagimumatically than goud Workshop prficgtice, yettlie (liscrepmiciw will be evident to those sk' led in the uit.

In the drawings in ll the and frame l0 of a rod rolling mill is illustrated, 'l1-l1@ jouinuls 11, l2 of the rolls having thremi whecls ui supplemental olls 13, 14 which will have 'bstween them thc liiiisliing pass. Tha. 1mi' 15 as it is fed to the, rolls is Olliptiufil in crosssection, as illustzitenl in Fig. 4, mul is n duced to a :found md 167 is illust-mimi in Fig. 3, in the 'lliuisliii'ilg pass. llim'v 'will be :i guido ET wrovidefl at the, buck of the Talla p'immil 'l`lw i l ilrvivv iw illu and which m n; liu-vingr cyliia' and lm openiu p0.

ul tlm r-2' chamber 22 m; f forming meuf zuid. a spifzilly so give the pmi; lili@ um?. Oli iii@ l of the Yulls' nlug trougli. ma am :i c

mutilated G i l *Hough will non im against soneto instance is shown as mounted upon ways 7 3 and may be moved toward the saw 74 by means si a hand wheel 7 The saw is shown as fast upon the sha-it 76 supported by bearings 77 and driven by means of a pulley 7S and belt 79 from sonic suitable source ot power. The saw will be rotated at a su iiciently high rate oi speed to do the4 proper cutting upon the cold hardened bar in the coil, and as the saine is fed to the saw in n. line coinciding with the plane of the saw blade, and with the axis ole the coil transverse to such plane, the cutting will produce spring lengths having the end laces of the end convolutions upon planes transverse to the anis ot the coil.

ln some instances the hardening of the coil will not be uniform throughbutthe entire cross-sectional area of the bar, that is it will be harder at or adjacent to the surface than it will be upon the interior. This is desirable in many instances and assuming" that the quenching action of' the bath was sufficient to cause a hardness down to a given depth from. the surface and the spring lengths having their ends beveled. before be ing plunged into such bath, the hardening action of the bath then would extend coinpletely through the beveled ends making them unduly brittle as compared with the rest of the spring, but by sawing the coil into lengths after it has been hardened a greater unifgrmity of hardness in the ends /will be maintained.

Applicant in the specification, and claim when employing the word tempering does not necessarily mean the techni/cal tempering of metal, that, is drawing the h/ardness or tempering the same down to the desircdhardness, but rather means in theconnnon use of the word treating apiece oi metal which has been brought to the proper degree oi hardness to to give it the desnable elasticity, whether such hardness has been produced at one op.- eration or whether ithas been produced by over-hardening, and then tempering or modifying such hardness, and following such use of the word has said that the springs are tcmpered directly` from the soiling device by being iilungcd in'to the bath.

By this present method time is saved, amount oi handling is reduced, the expense of second heating done away withhand not only are these economies had, but a superior article is produced owing to the sheen-ee of scale being raised. by coolingY upd reheating, and also by the roll-finish of the surlzufe being maintained and not opened by reheating.

The term billet as used herein hirn gen eral application to the mass of metal to be Aished spring-coil.

reduced to the bar or rod and without reference to any peculiar technical distinction :from other masses of metal known by difiercnt names. And likewise the word bar as used in the claim is used literally and not technically.

When it is stated that the coil is tempered at the billet heat it, ofcourse, means the heat imparted to the metal in the coil when 'such metal was in the billet, and not to the temperatu re of the billet which is in excess ot' the temperature of the metal after it has left the I ceiling device.

ln carrying out my improvement in spring making there is a direct co-action between the rod-forming driving rolls and .the coiling die in such manner that the bite of the rolls upon thel rod incident tothe reshaping of the rod immediately as driven Jforward into the ceiling die operates to create. a suflicient driving power for successfully torcinor the perfectly formed bar into the die, and by means, it will be observed, the resistance of the ceiling die is overcome by driving power created not by the mere impingement of frictional driving rolls upon a finished rod, but by the resistance due to the transformation of the rodirom one sectional form into another, the latter form being the one which it is required the rod'shall have in the finln this connection it will be remembered that owing to the large sizes or" the rods required in many cases as compared with the diameter of the finished coil the resistance of the coiling die is relatively large, and that 4in the rolling of rods'the subjection of a heated rod ofcircular cross-section to the heavy roll-pressurev which would be re uired for properly feedin a fully formeil rod to the ceiling die woul of itself, operate to impair or destroy the required true and circular form .of the rod as this passes into the die. By means of my present improvements, however, I so combine together into one operation the rod-sha ing and rodcoilingr that each co-acts direct yand immediately with theother in the production of this two concurrent results which include the resha ing of the preliminarily formed bar into its nal form and the ceiling of the finished bar through the power used 1n the reshaping ot the preliminarily formedbar. Thus the two results required are simultaneously and rapidly accomplished on the same bar, with the exception of course thatia very short piece, extending across the short distance between the bite of the rolls and the coiling die, remains,.this piece, however, being so small that it may in practice be neglected. There is a concurrence in action as regards the bar in the shaping and ceiling.

The changing of the bar from an oval cross-section toa round cross-section is a heat produc-ing operation, as also the 'coiling but in most instances to a less degree.

Aml tlimsa wiioii properly carried out, as herrin coulemplzilml, will Conserve lili@ limit ,in llielmr for Lim subsequent luu'dening.

A smiling that the outer shell or 7,0110 Ol l, the bur is collier than the inner zone or coi-0, upon tlm quenching 0l the bur 'the outer Zone. which was under uoi'itriicvlzile stress, cools l do'wn upon the core which was uorrrmllyg under expansive or prcsguru :unl upon the Completion of cooling the inter-pressure of the zones will not be so great :is where tlm shell is the hotter or where :i uniform temp@- avure exists throughout the lmr, n 11d when the bur so hardened i5 in lli@ 'forni 0l n coiiml spring the .torsion in the bnr incirloiit fo ilzc compression :incl expansion 0i' such ,spring will bef more readily :icuonimoilailml by flirv bar, since there will be zx, coudibioii existing' l Within the bar which will permit flic expansion in the torsion anal the Conti-umich in tlm returning independently of the core which,

l D l will non break readily under alla no i rolling l'lif, bi

bil/ing :ill the m3 f 'Ypzinisive or slrctciiiijj th mision i@ time exim or out@ zum, 'lliUS stress as when the Snell has gr/atar pinch .ing :1L imi upon @liv Core when hardened.

lim/'mg thus; clescrilieal my iiwm Voir, i Claim: i

"lie art whirl). Coiisiisls in healing f 1 im@ n, lmr, fmiiiing lie 521.111 im' into n coil, :md liziiflmii lie said il al' the limi rmriziiiiirigl irl'cr lli@ iollil'igjj, @fifi o\' liiig-.

O l Biliirrsiy slrfulj New RUSSELL? YL --w'r l1 man! J primi. 

